Purification and Characterization of an N-Terminal Acidic Amino Acid-Specific Aminopeptidase from Soybean Cotyledons (Glycine max)
作者:Minao ASANO、Nami NAKAMURA、Misako KAWAI、Tetsuya MIWA、Noriki NIO
DOI:10.1271/bbb.90617
日期:2010.1.23
A novel enzyme that catalyzes the efficient hydrolysis of Glu-Glu was isolated from soybean cotyledons by ammonium sulfate fractionation and successive column chromatographies of Q-sepharose, Phenyl sepharose, and Superdex 200. The apparent molecular mass of this enzyme was found to be 56 kDa and 510 kDa by SDS-polyacrylamide gel electrophoresis and Superdex 200 HR 10/30 column chromatography respectively. The enzyme had high activity against Glu-p-nitroanilide (pNA) and Asp-pNA, whereas Leu-pNA, Phe-pNA, Ala-pNA, and Pro-pNA were not hydrolyzed. The synthetic dipeptides Glu-Xxx and Asp-Xxx were hydrolyzed, but Xxx-Glu was not. The digestion of a Glu-rich oligopeptide, chromogranin A (Glu-Glu-Glu-Glu-Glu-Met-Ala-Val-Val-Pro-Gln-Gly-Leu-Phe-Arg-Gly-NH2) using this purified enzyme was also investigated. Glutamic acid residues were cleaved one by one from the N-terminus. These observations indicate that the enzyme removes glutamyl or aspartyl residues from N-terminal acidic amino acid-containing peptides. It is thought that it was an N-terminal acidic amino acid-specific aminopeptidase from a plant.
通过硫酸铵分级和 Q-sepharose、Phenyl sepharose 和 Superdex 200 连续柱层析,从大豆子叶中分离出一种催化 Glu-Glu 高效水解的新型酶。该酶的表观分子量为 56 kDa分别通过 SDS-聚丙烯酰胺凝胶电泳和 Superdex 200 HR 10/30 柱层析得出 510 kDa 和 510 kDa。该酶对 Glu-p-硝基苯胺 (pNA) 和 Asp-pNA 具有高活性,而 Leu-pNA、Phe-pNA、Ala-pNA 和 Pro-pNA 不被水解。合成的二肽 Glu-Xxx 和 Asp-Xxx 被水解,但 Xxx-Glu 没有被水解。使用这种纯化酶消化富含 Glu 的寡肽嗜铬粒蛋白 A (Glu-Glu-Glu-Glu-Glu-Met-Ala-Val-Val-Pro-Gln-Gly-Leu-Phe-Arg-Gly-NH2)也被调查。谷氨酸残基从N末端一一被切割。这些观察结果表明该酶从 N 末端含酸性氨基酸的肽中去除谷氨酰或天冬氨酰残基。人们认为它是一种来自植物的 N 末端酸性氨基酸特异性氨肽酶。